Winter Weather — Plymouth, Iowa

2020-11-09 to 2020-11-10 · Plymouth, Iowa

Event narrative

A mix of sleet, freezing rain and freezing drizzle overnight and much of the morning accumulated ice to around a tenth of an inch, especially on elevated surfaces. Slick roadways resulted in an rollover accident along U.S. Highway 75 northwest of Le Mars, causing a pair of (indirect) injuries to the driver and one passenger, and (indirect) fatality to a backseat passenger. Precipitation changed to snow late morning, briefly heavy between 1200-1500CST. Snowfall totaled 5.3 inches at Arkon, 3.7 inches at Remsen, and 3.3 inches at Le Mars. Property damage costs are rough estimates.

Wider weather episode

Unusual warmth with a week of temperatures mainly in the 70s (even 50s and 60s on November 9 less than a day before this storm) was brought to an abrupt end as a deep trough of low pressure moved out of Rockies and into the Plains. An intense lower- to mid-level frontal zone oozed eastward as a strong jet lifted out across the Plains on November 10, initiating widespread precipitation. More rapid shallow cooling occurred across northwest Iowa and led to a swath of freezing rain which accumulated from a tenth to a half inch during the overnight and morning hours, before changing to snow in the afternoon. Heavier and more persistent snowfall occurred with the deeper cooling to the northwest across southeast South Dakota, far northwest Iowa and southwest Minnesota, where amounts ranged from 3 to 7 inches.

Source: NOAA Storm Events Database, event_id 928610. Narrative written by the NWS forecast office that issued the report.